Safety Study of Nebulized Sodium Nitroprusside in Adult Acute Lung Injury

Inclusion Criteria:

1. Age ≥ 18
2. Negative β-hCG in women of child bearing age (age ≤ 50)

3. Developed ALI within past 72 hours:

   • PaO2/FiO2 < 300;
   • Bilateral infiltrates on CXR;
   • No clinical evidence of elevated left atrial pressure ie. Heart failure as the cause of hypoxia and bilateral infiltrates; and
   • Recognized risk factor for ALI such as: pneumonia, aspiration pneumonitis, acute pancreatitis, massive blood transfusion, or sepsis
4. FiO2 ≥ 0.5
5. PEEP ≥ 8 cm H2O
6. Invasive arterial blood pressure line
7. Endotracheal intubation or tracheostomy
8. Conventional mechanical ventilation
9. Mean Arterial Pressure (MAP) ≥ 65 mmHg with or without use of vasopressors (stable for at least more than 1 hour)
10. Arterial pH ≥ 7.15

Exclusion Criteria:

1. Chest tube with active leak (eg. bronchopulmonary fistula),
2. Prone ventilation, inhaled nitric oxide, inhaled prostacyclin, high frequency oscillatory ventilation,
3. Lack of consent,
4. Untreated coarctation of aorta, symptomatic or severe/critical aortic stenosis as documented by echocardiogram or clinical history,
5. Evidence of increased intracranial pressure (eg. dilated pupils, known intracranial trauma or mass on head CT),
6. SpO2 <90%,
7. Contraindication to SNP i.e. hypersensitivity, congenital optic atrophy, tobacco amblyopia,
8. Active treatment with IV or transdermal nitroglycerin,
9. G6PD deficiency
10. CrCl < 30 ml/min or receiving renal replacement therapy, or
11. Total bilirubin > 68 µmol/L and AST or ALT level 2 times the upper limit of normal.